Process for converting hydrocarbons of low molecular weight



F. E, FREY 2,270,700

PROCESS CONVERTING HYDROCARBONS OF LOW MOLECULAR WEIGHT Jan. 20, 1942.

Original Filed yJune '1, 1956 `intomotor fuel.

Patented Jan. 20, 1942 UNITED` s'lATlzs PATENT" OFFICE Aazimut l ROBCESS vFOR` (JONVERTINGI HYDROCAR- BONS OF LOW MOLECULAR WEIGHT Frederick E. ma'sruvlue, ons., assigner a Phillips Petroleum Company, a corporation of Delaware Application 'June 1,1936, serial No. 82,954 ltenewedNovember 7, 1939 (Cl. ISG- 10) 24 Claims.

-l clusion in motor fuel into normally liquid hydrocarbons suitable for motor fuel.

It has been proposed to convert normally gas# eous hydrocarbons into normally liquid hydrocarbons by heating to a temperature at which reaction takes place while maintaining Aa high pressure and at the same time converting thev less reactive hydrocarbons by pyrolyzing them at a high temperature and -low'pressure to produce gaseous oleilns which may be mixdwith the hydrocarbons subjected to the pressure conversion step.

'I'his present invention is a continuation-in\ part of my copending application Serial No. 12,931 med March 25, 1935,'wh1cn issued January 4, 1938, as Patent 2,104,296 and which in turn is a continuation-in-part of my application Serial No. 731,920 led June 22, 1934 which issued on May 21, 1935, as Patent 2,002,394 which constitute improvements resulting in increased A'yield of higher molecular weight hydrocarbons and consists essentially in introducing olen rich hydrocarbons to predominantly saturated hydrocarbons while maintaining a thermal reaction temperature ,level for' a period o! time4 during l which reaction takes place,-the olen rich hydrocarbon being introduced to the paramn at a plurality of times during said reaction period or continuously during said period.

The present invention has for one object an improved process for utilizing ethylene in agas conversion process..

A further object is to provide an improved process for utilizing ethane and methane as conversion stock in conjunction with parafflns higher than` ethane.

Another object is the conversion 'of the lowerv paramns under conditions which will produce a particularly high ultimate yield ofproducts oi higher molecular weight. Another object is ,the control of volatility in these products while maintainir" a high ultimate yield thereof.

Anrther'object is. the eiiecting of economyin separating operations.

Another object is the conversion of light hygether withtbosef lfrom pressure still-oilcracking to effect a particularly eiiicient conversion of paraffin pressure of oleflns should be low in comparison olen will not take place `drocarbons from Jvapor phase oil .cracking totions, which yield simpler 4tion temperature A still further object is the production of hydrogen.

Other objects and advantages will be apparent as the description of the process proceeds.

I have previously found that the simple olens and paraiiins undergo cooperative reaction when subjected to a conversion temperature under high pressure in the processes above. referred towith introduction of the olenn to the parafn not wholly before reaction, but during the course o! reaction, and thereby produce ahigher ultimate yield of gasoline than is obtainable inthe conversion by heat and pressure o'i olens and paraiilns separately. are not 'fully understood, but the yield increase appears to be largely due to the'direct union and olefin molecules. The partial with the partial pressure of the paramns in order that the concurrent polymerization oi.' olen with to too great an extent, yet the absolute pressure should be suiiiciently high to cause synthesis reactions to predominate and to suppress considerably the splitting reacgaseous hydrocarbons at the expense of higher hydrocarbons. The higher the pressure the higher the ultimate yield o! the normally liquid hydrocarbons which may be developed per thermal treatment without their partial destruction by cracking. pressure, however, increases the rate o! union of olefin with olefin and the introduction of olen "should accordingly take placeat an increased numberof points in the reaction period or be more thinly dispersed during the reaction to obtain the maximum advantage in yield increase.

Introduction of olefin may take place thus at a plurality of points disposed along an elongated reaction tube through which the parafiln rich gases flow while a reaction temperature is maintained. Alternatively an equivalent introduction of olen may in effect be made at fewer points or .even a single point by introducing olefin to a circulated stream of parailin exposed to a reacwherein the stream passes repeatedly the point or points of olefin introduction, passing then through the thermal reaction zoneand back to the point of olen introduction. A plurality of such of which oleiin is introduced.. and so arranged that the hydrocarbon stream passes through them serially may be used. In general dispersal of oleilns inthe paraiiin is applied after the onset or during reaction. By the introduction of oleiin a plurality of times during the course of the The reactions taking place Increase -in circulating elements to each j axeaorintubecoils4 of oleiin introduced,

wide limits, from heating and reacting period, will be understood the use o! any of these methods as described or their equivalents which Awill be obvious. The high pressure conversion may be eile'cted in accordance with the foregoing description in either reaction chambers of enlarged cross sectional and passageways ofrestricted crosssectional area, and the term reaction chamber or reaction zone" in this connection will be understood to refer to either type of reaction vessel. A

The overall conversion conditions of time and temperature for the pressure conversion steps will in general be somewhat milder than the -known thermal decomposition time-temperature relationships. 'I'he temperature'will vary from 4800 to 1200 F., the highertemperatures being required for the conversion of the'more refractory parailins and will-be readily determinable by experiment. Methane and ethane undergo reaction with added oleflns with comparative dimculty, while propane', butanes and pentanes are more readily converted. The conversion temrature is not greatly dependent on the species whether ethylene, propylene, butylenes, or mixtures in which they may occur as the predominating olens in various ,relative proportions. However, ethylene is the most'favorably situated oleiln in respect to thermodynamic driving force for paraiiln-oleiin union. A part of the ethylene so introduced,"usually survives reaction as ethane and may be converted into unsaturated hydrocarbons by pyrolysis 'and returned to the pressure conversion step.,

The pressure under which the pressure reaction of oleiln with paramn is conducted should in general exceed about 500 pounds per square inch.

the paraln-olen reaction increases with increase of pressure, and pressures as high as 5,000-10,000 pounds per square inch and more may be used to advantagev in appropriate situations, and the concentration of olefin accordingly, with increased efllciency as the pressure increases. A steady-state concentration of olefin is established at -30 per cent under 1,000 pounds pressure, depending somewhat on the actions taking place slightly. 'I'he number oi points of oleiin addition may be suitably that which provides at each addition nov more than and preferably much less than a quantity of cleiin equal to the several per cent to 30 per cent and more of the total hydrocarbon present. An attempt to react the greater part of the parafnic hydrocarbons in a sing however, results in degradation of a part ofthe gasoline formed, and it is usually desirable to react the paraiiins partially, remove gasoline, and again react the paralns with oleiin. The quantity of olefin added may vary from considerably less than to more'than the molal equivalent of the parailln entering reaction while retaining the advantage of an augmented yield accompanied by more'or less olefin-olefin polymerization and splitting reactions.

In the present invention, by pyrolyzing parafle thermal treatmenty iins in one stage to produce oleiins and/or acetylstel). with a under pressure as described, higher yieldsof gasoline are obtainable under practical and economical conditions than can be obtained either by conversion in a single stage by heat and pressure while returning all suitable unconverted parailins, or by pyrolyzing paraillns to produce oleflns which are then polymerized by heat and pressure to produce gasoline. i

In the simple conversion 'of propane, for example, by heat and pressure, the ethane produced by the thermal treatment may be pyrolyzed to produce ethylene, which is then admixed with propane and subjected to the pressure conversion resultant increase in gasoline yield. Especially if the ethyleneso produced is added portionwise, or in an equivalent manner, to the propane undergoing pressure conversion, in accordance withfthe present invention, is the gasoline yield high and the production of ethane and methane low, at low pressure, or other hydrocarbons from.. an extraneous source -may be required to produce the volume of oleiins needed for the cooperative reaction with propane.- In this waya particularly high gasoline yield may be obtained, to-

form of apparatus for gether with a reduced formation of heavy hydro-y carbons of less value than gasoline.

The drawing diagrammatically illustrates onev carrying out the process.

The operation of the process should be readily understood upon consideration -of the following description which is made with reference .to they drawing. A conversion stock, which may be composed for the most part of parailin hydrocarbons higher thanr conduit I0 and passed ethane, is introduced into therethrough to a pump-II whereinthe pressure of the charging stock is raised to a thousand pounds per square inch or more. The hydrocarbons comprising the charging stock then ilow through conduit I2 from which they pass into a reaction chamber or zone such as the coil I3 into which hydrocarbons rich 4 'in ethylene are vintroduced in a manner to be later described. Within'the reaction chamber or zone such asthe coil I3 thermal treatment of the' mixed' hydrocarbons takes place at an elesteady-state concentration mainvated pressure and at a temperature of 800 to' 1200". F. to produce hydrocarbons of higher molecular weight. After thermally treating the hydrocarbons in this manner they pass from the coil Il through the conduit I4 to aseparator I 5 in which the hydrocarbons of high molecular weight are removed and discharged through conduit `lfby which means these hydrocarbons are passed to the separator H wherein heavy products are separated and discharged by way of the conduit It, controlled by the valve I9, and hydrocarbons of motor fuel boiling range are removed from the separator I 'I through the conduit 20 and after being reduced to a liquid -by passing through the condenser 2| are withdrawn by way of pipe 22 controlled by the valve 23. vInto the separator I l there may be introduced through the conduit 25 controlled by the valve 24 hydro^l carbons containing the components intended for the conversion in this bons remaining in the separator IIS, which will be predominantly normally gaseous, pass throughthe conduit 26 to another separator 21m which whereby the pyrolysis of propane process. Theh-ydrocarcompressor 46 in which the 4sorbed. The ethylene-bearing liquid is dis- 23, the latter beingcontrolled by the valve 36, or these hydrocarbons so discharged from the separator 21 may'be returned through the conduit 3|, which is controlled by the valve 32, and returned to the conduit I6 where they are mixed 5 with low molecular weight hydrocarbons comprising the fresh conversion stock and which together with the hydrocarbon introduced by way of conduit-3| pass through the conduit I6 to the pump II. 'I 'he lighter hydrocarbons from sepal0 rator 21 which may consist mostly of methane and ethane, will pass through conduit -33 to a separator 34' in which part or all of the methane -and lighter gases are separated and if desired are discharged through the conduit which is con- .1 trolled by the valve 36. In thismannera hydrocarbon s tream, more or less predominating inl ethane, is obtained which is withdrawn from the separator 34 by way of the conduit 31. The. separation in the separator 34' may be eiected 20 either with the aid of low temperature which will allow the condensing of the higher hydrocarbons present, or oil absorption, oran equivalent methodmay be used.

The hydrocarbon which may predominate in ethane, which is withdrawn from the separator 34 by way ofthe conduit' 31 may be discharged through conduit 36 and valve 36, or it may be passed through conduit 46 toconduit-4I wherein it may be mixed with hydrocarbons entering the system, and the mixture is then passed to al 1 secon reaction chamber or zone such as the coil 42 which may be conveniently a tube coil, wherein it is pyrolyzed at a pressure below 500 pounds per square inch, which maybe as low as atmos- `pheric lor sub-atmospheric. 'I'he pyrolysis temperature within the reaction chamber or zone such as the coil 42 is vabovel about LQOO" F. and' may exceed 1,700 F. when a gas mixture particu-S larly high in methane -is supplied. The products .m

of pyrolysis pass from the coil 42 through a,' conduit 43 to a separator 44 in which tar and, lighter normally liquid hydrocarbons are removed or discharged through the conduit 45 controlled by the valve 46. The hydrocarbons re- 4r,

lmalning within the separator 4.4 willcontain -a substantial portion usually from 10% to 45% by volume oi.' unsaturatesof low'molecular weight principally ethylene and acetylene. These latter materials will then pass through conduit 41 to a 5u pressures thereof are elevated sufhciently to facilitate subsequent separations and usually to a pressure of 200 to 1,000 pounds per square inch. or they maybe by-passed through conduit 41A controlled by the 55 valve 41B. The hydrocarbons are then passed through the conduit 46 to a separator 66 wherein normallyliquid hydrocarbon as well as a part of the less volatile gaseous hydrocarbons-may, if desired, be removed or discharged through the con- 60 duit 5I, and the conduit 62 which is control led by the valve 53. The hydrocarbons remaining in the separator 50 will then pass therefrom through the conduit 54- to a separator Il wherein methane and lighter gases aremore or less completely re- 65 moved with the aid of low temperature, absorption methods, or the equivalents thereof, and discharged through conduit' 56. These gases are often rich in hydrogen and constitute a source In some instances the hydrocarbons 70 h conduit III and the pump II may vantage as anabsorbent and mayv conduit 51 controlled bythe valve il and introduedto the separator' 55 wherein 'ethylene and highe'botiing hydrocarbons are ab- :s

and therefore a part of my invention duit I6,passi charged from separator 55 through the conduit 56 and is carried thereby to the pump 66 and is forced thereby through the conduit 6I into the header 62 from which it iiows into the conduits 63, 6'4, 65,` 66, and 61vwhich are controlledby/l the valves 66, 66, 16, 1I, and 12 respectively, and is thus introduced into the coil I3 at a plurality of points. It is to be understood that the valves- 66, 69, 10, 1I and 12 which control the introduction o! the ethylene-bearing liquid to the coil. I3 through the pipes 63, 64, 65, 66 and 61 respectively, may be so operated as to introduce the ethylene-bearing. liquid through any. or all of these pipes or feasible combinations thereof,

`and/or these valves may'be utilized merely to regulate the quantity and/or flow of the ethylenebearing liquid so introduced to the coil I3. Reaction takes place throughout that part'of the coilinto which the ethylene-bearing liquid is introduced sumed by the reactions before the fluid passing through the coil I3 reaches a subsequentpoint oi.' olefin introduction. The ethylene-rich con-- centrate may alternately beisolatedand passed v through the conduits 63, 64,65, 66 and 61 with- `out the` presence of thev absorbing medium.-

Hydrocarbons dischargedfrom the separator 5I! throughthe conduit 5I may when desired be passed through conduit .=13'\which is controlled by the valve 14 and-passed lto the separator I5 wherein thehavy hydrocarbons will'be discharged with the higher molecular weight prod- .ucts .of4 'the higher pressure conversion step through the' conduit I6.

'1: In my process the hydrocarbonslighter than thergasoline which are discharged from conversion coil I3 will in many cases contain relatively -`small amounts of the lightest'hydrocarbons such as result from splitting' reactions. It is an object to effect economy in the separating operations. Accordingly apart of the hydrocarbons lighter than gasoline which passfthrough conduit 26 from the separator I5 may be'withdrawn through the conduit 15, valve 16, cooler 11, pump `16, and passed to conduit 3| and thence through conduit III to vthe'pressurereaction coil I3.

It is also an object and a part of my invention to vary and control the volatility of the liquid hydrocarbons produced, independently of the composition of conversion stock, while realizing a high yield of such liquid hydrocarbons whether theybe o f high or-lowerl volatility. I have found that the lighter components of the gasoline produced, which are primarily paramnic, may be 'emciently caused to combine with simple oleiin's or acetylene. Ihus pentanes and hexanes yield re- 'spectivly heptanes andoctanes when reacted with ethylene. In order to 'eil'ect reductionv in volatility I may return such hydrocarbons synthesized in my process to the pressure conversion coil to be reacted with simple unsaturates.-

.Thus separator I5l may be loperated in such amanner that more or less of .the light gasoline hydrocarbons,v otherwise discharged with 'the higher molecular weight products through connstead through conduit 26 together with the lighter hydrocarbons, which' are separated with the lighter hydrocarbons whereturned to reaction coil I3 in separator 21 and pass-through conduit 26, valve 32, conduit 3I, to conduit I6, and pump II, Vand thence through conduit I2 to the conversion coil I3.

The unconverted gaseous hydrocarbons are of and the oleiin produced is largely conlight hydrocarbons predominating in I motorfuel. Under the operating conditions given low olen content, usually of the order of or i less, and are suitable for returning to the pressure'conversion as a virtually paramnic stock for reacting again with olen. A conversion stock such as cracking still gases containing a higher 5 concentration of olen may be introduced as a source of olefin for dispersing in the paraihnic stream within the reaction zone and may accompany oleflns derived from low pressure pyrolysis. In such a case the fraction o f olen-depleted l propane, butane and sometimes pentane, which may be separated from the eilluents oi' the pressure conversion step, constitutes a suitable paraillnic stock for reacting with such more highly. oleflnic hydrocarbons. y

'Ihe process is designed primarily to produce normally liquid hydrocarbonsfsuitable for motor fuel, which ',distill below about 400 F. Hydrocarbons suitable for introducing through conduit l0 to the pressure conversion step are particularly propane and the'butanes and also-pentanes in those cases in which the volatility they exit is too high for direct use as ingredients in the hydrocarbons discharged from the pressure conversion eiected in the reaction coil I3, boiling below the gasoline range and recycled through conduit 3|, will be depleted in olens but contain from a trace to a few per cent of ethylene, propylene, butylenes and, in some cases, pentenes.

The fresh conversion stock for the process entering through conduit III may either consist of the'simple paraflins-propane, butane and pentane-obtained from oildistillation, natural gas or as a product of any olefin depleting prior operation applied to the volatile products of a cracking operation, ormay be hydrocarbons of equivalent boiling range containing a substantial proportion of oleflns such as condensate from gases derived from pressure still cracking of petroleum. Any ethylene present contributes to the yield -of. hydrocarbons but ethane and 4 methane in many cases are diillcultly converted' in the pressure conversion step and survive to be isolated in separator 34 and passed to the pyrolysis step in coil 42. The gases subjected to the pyrolysis step in coll 42 are preferably of lowolen content and predominating in ethane, but these gases may contain more or less of higher hydrocarbons. Hydrocarbons suitable for' the pyrolysis may include any of the gaseous hydrocarbons, or higher hydrocarbons, other than highly aromatic oils. 'I'hey may be derived from the normally gaseous eiu'ents of the pressure conversion operation, and from the other sources set forth, especially when thequantity available from the pressure conversion is insumcient for taking maximum advantage of the coopera-- tive parailln-ole1in reaction. The pyrolysis maybe carriednout without catalyst at temperature above 12.00 F. and pressures below 500 pounds per square inch under well knownconditions whereby, splitting reactions are eii'ectedr and usaturated hydrocarbons, containing. a more or less large proportion of ethylene are produced. Catalysts may be used to assist in the formation of such unsaturated hydrocarbons. The pyrolysis operation may produce also more or less of norj mally liquid hydrocarbons, but normally gaseous unsaturated hydrocarbons are at the same time obtained for, reacting with paraiiins under high. pressure. and while a pressure below 500 pounds per square inch and temperature above about 1,000? F. lead to relatively high yields of nor- 15 source of oletlnic reactant.

, inate when gaseous hydrocarbons are pyrolyzed produced. 0n reacting these olei'lns under mally gaseous unsaturated hydrocarbons, a higher pressure or lower temperature may be used with some sacriiice in yield of such unsaturated hydrocarbons. The method of cracking oil known as vapor phase cracking in which such conditions are employed yields gasoline together with ethylene-rich gases which may serve as a Thus vapor phase cracking of oil. may constitute Acetylene, rather than ethylene, may predomand the pyrolysis temperature is particularly high but' both are highly suitable for the process.

1700u F., under well known conditions, and

acetylene is particularly suitable for reaction by' portionwise addition with the paraiiins, the polymeric hydrocarbons so produced being largely olenic and paraflinic, and unlike the carbon rich polymers ordinarily obtained in polymerizing acetylene. The simple polymers of acetylene which may be derived from acetylene, and

`butadiene may also be reacted with parailins in the same Way. While methane and ethane are reacted only slowly with the oleflns and in many cases are preferably not present in considerable amount in the parains subjected to the high pressure conversion step, they will enter into-reaction more readily with acetylene, and accordingly may advantageously be present when acetylene-rich gases are introduced to the parafnic reactants.

As an example of the loperation of the process, propane under a pressure of 4500 pounds per square inch was reacted with ethylene produced by pyrolysis and containing a small amount of propylene, at 940 F. for 3.8 minutes, the ethylene being introduced in 40 small portions spaced throughout the reaction period. In this way an average ethylene concentration of 2.0 to 2.5 per cent by weight was maintained throughout the .reaction period. Seven per cent by weight of ethylene was introduced and 1.5 per cent survived unreacted. A trace of methane was formed, very small amounts of ethane, propylene and butane-butylene were produced, and- 12.5 percent by weight of normally liquid hydrocarbons, based on the quantity of propane plus ethylene thermally treated, was produced of the following composition.

Per cexit by weigh;

reaction products and pyrolyzing at low pressure' the ethane together with added propane, ethylene, plus a small amount of vpropylene are equivalent of propane under the conditions described, liquid hydrocarbons suitable for gasothe pyrolysis step.

Acetylene may be 4produced by applying the v 4500' pounds per square inch pressure with a molal iinic hydrocarbons, which comprises passing -iirst reaction zone containing said normally gassaturated hydrocarbons, passing a further pord 2,270,700 line are produced. A yield of '85,pei cent weight -approximate steady-state concentration of ethylene leading to eiiicient conversion, in the example, 2 per cent, it is evident that 4 or 5 points of olen addition would have been lsuilicient' in number yto provide increments commensurate with and slightly lessthan this steady-state ethylene concentration.4

Iclaiin: f 1. A process for converting hydrocarbons of. low molecular weight to hydrocarbons of higher molecular weighi-I which comprises subjecting in a first reaction zone a hydrocarbon fluid coritaining predominantly lower paraiiins and an added quantity of acetylene to a pressure above 500 pounds per square inch and a temperatureD between 800 and 1200 F. consuming said parafns and acetylene and producing hydrocarbons of higher molecular weight, subjecting in a.sec ond reaction lzone gaseous hydrocarbons to a pressure below 500 pounds per square inch and a temperature above- 1200- F. to form pyrolysis products, separating from the pyrolysis products a fraction rich in acetylene and introducing the 3:, said fraction into the said first reaction zone a plurality of times during the course of the passage of the hydrocarbons passing therethrough, removing from the said first reaction zone the thermally treated hydrocarbons and separating therefrom the hydrocarbons of higher molecular weight produced.

2. A process for producing gasoline boiling range hydrocarbons from predominantly parafnormally gaseous predominantly parainic hydrocarbons through a iirst .reaction zone and therein subjecting said hydrocarbons to a pressure less than 500 pounds per square inch and,

to a reaction temperature for a period of time suiiicient to produce normally gaseous unsaturated hydrocarbons of the class consisting of normally gaseous olens, acetylenes, and butadiene, passing a portion of the eiiiuents of said eous unsaturated hydrocarbons to a separating zone, compressing a mixture of predominantly paradinic hydrocarbons of not less than three nor more than six carbon atoms per molecule to a pressure in excess of 500 pounds per square inch and subjecting a portion of said 'mixture .in a secondI reaction zone to a temperature of 800^to 1200 F. causing reaction to take place consuming paramns and subsequently added un- 3. Av process for converting hydrocarbon mixtures of low molecular weight predominating in paratlin hydrocarbons into higher molecular weight hydrocarbons, which comprises coml pressing a predominantly paramnic normally .gaseous hydrocarbon mixture to a pressure between 500 and 5000 pounds per square inch and subjecting a portion of said mixture in a first `reaction zone to a temperature of 800 to 1200 F., passing a further portion of saidmixture as an absorbent fluid to a separating zone and introducing a hydrocarbon mixture containing normally gaseous unsaturated hydrocarbons of the class consisting of normally gaseous olens, acetylenes, and butadiene producecrin a second reaction zone to said separating zone, absorbing said normally gaseous unsaturated hydrocarbons in `said absorbent iiuid and introducing the resultant mixture into said iirst reaction zone.

4,second reaction zone and therein subjecting normally gaseous hydrocarbons to a 'temperature in excess of 1200 F. while under a pressure less than 500 pounds per square inch-for a period of time such that an optimum yield of normally.` gaseous unsaturated hydrocarbons of the class consisting of normally gaseous oletlns, acetylenes, and butadiene are produced, and passing said unsaturated hydrocarbons `to the aforesaid sep-,V arating zone.

4. A process for converting hydrocarbons of low molecular weight into a motor fuelof low and controlled volatility, Awhich comprises introducing to a process an initial hydrocarbon mixture comprised predominantly of paraiiin hydrocarbons of not less than three and not more than ilve carbon atoms per molecule, adding thereto a recycle hydrocarbon mixture comprised of predominantly parailln hydrocarbons oi' not less than three nor more than six carbon atoms per molecule, subjecting a tlrst portion of said added mixtures in a irst reaction zone to a pressure of between 500 and 10,000 pounds perA squ'are. inch and to a temperature of between 800 and 1200 F., concomitantly subjecting la normally gaseous hydrocarbon mixture in a second reaction zone to a' pyrolysis temperature in excess of 1200 F. while under a pressure less than 500 pounds-per square' inch for a period of time suflicient to produce normally gaseous unsaturated hydrocarbons ofthe class consisting of normally gaseous oletins, acetylenes, and butadiene, passing a portion-of the emuents o! said reaction zone containing said normally gaseous unsaturated hydrocarbons to a separating zone, passing a second portion of said added mixtures as an absorbent iiuid to said separating zone whereby normally gaseous unsaturated'hy drocarbons are absorbed in said iiuid. adding to said portion ofadded mixtures in said rst re action zone said normally gaseous unsaturated hydrocarbons and said absorbent duid in a manner such that the total concentration of 'unsaturated hydrocarbons does not exceed about 30 per cent in said rst reaction zone, separating fromI the emuents ot said nrst reaction zone a first fraction comprised voif a gasoline boiling range www..

hydrocarbon mixture of a low and controlled volatility and removing it from theprocess, separating a second fraction comprised of predominantly paraflln hydrocarbons of not less than three nor more than six carbon atoms per molecule and containing controlled amounts of hydrocarbons of iive and six carbon atoms per molecule and returning said fraction to said iirst reaction zone as said recycle hydrocarbon mixture, and further separating a third-fraction of a lower average molecular weight than said second fraction and passing said third fraction to said second reaction zone. e

5. A process for producing gasoline boiling range hydrocarbons from predominantly parafflnic hydrocarbons, which comprises passing predominantly paraillnic hydrocarbonsv through a rst reaction'zone and therein subjecting said hydrocarbons to a treatment under a pressure less than 500 pounds perI square inch and to a reaction temperature in excess of 1 000 F, for aperiod of time suilicient to produce normally gaseous unsaturated hydrocarbons of the class consisting of normally gaseous olei'lns, acetylenes, and butadiene, passing at least a portion of the eilluents of said rst reaction zone containing said normally gaseous unsaturated hydrocarbons to a separating zone, introducing to said process a jecting said compressed mixture in a second re,

action zone to a temperature between 800 and 1200 F., causing reaction to take place consuming parailins and subsequently added unsaturated A'1. A process for reacting paraffin hydrocarbons with unsaturated hydrocarbons to producepredominantly paraillnic products of higher molecular weight including gasoline boiling range hydrocarbons of controlled volatility which comprises charging a predominantly paraiinic hydrocarbon mixture oi. between 2 and 6 carbon atoms per molecule to a reaction zone, admixing therewith unsaturated normally gaseous hydrocarbons of the class consisting of normally gaseous oleilns, acetylenes, and butadiene in such quantity that the total concentration .of unsaturates in the reaction mixture at no time exceeds maintaining a reaction pressure exceeding 500 pounds' per square inch and a reaction temperature between 800 and 1200 F., in said zone 8. A process for converting hydrocarbons of lowv molecular weight into hydrocarbons of higher molecular weight, which comprisessubjecting lin a tlrst reaction zone a predominantly paraiiinic hydrocarbon fluid composed of hydrocarbons of not more than 'six carbon atoms per molecule and added normally gaseous unsaturated hydrocarbons of the class consisting of nor- Amally gaseous olens, acetylenes, and butadiene to a pressure above 500 pounds per square inch and a temperature between 800 and 1200 F. for

hydrocarbons, passing a further portion of said mixture to said separating zone under a suitable pressure as an absorbent liquid and absorbingl 40 being added in a total amount between 2 and 30 therein normally gaseous unsaturated hydrocarbons of the class consisting of normally/gaseous; oleilns, acetylenes, and butadiene and introduc-l ing the resultant mixture under a pressure be tween 500 and 10,000 pounds per square inch and in amounts not to exceed thirty per cent of unsaturated hydrocarbons inthe reaction mixture to said second reaction zone a plurality of times during the course ofthe passage'of the hydrocarbons passing therethrough,'and ilnally passing a hydrocarbon stream vfrom said second reaction zone to a separating zone and separating therefrom gasoline boiling range hydrocarbons.

6. A process for converting parailin hydrocarbons of two or more carbon atoms per molecule to gasoline boiling hydrocarbons of controlled volatility, which comprises subjecting predominantly parailln hydrocarbons admixed with normally gaseous unsaturated hydrocarbons ofthe class consisting of normally gaseous olennaacetylenes, and butadiene in such a manner that the total concentration of unsaturates in the mixture at any onetime does notexceed 30% to a temperature between 800 and 1200 F., and a pressure -greater than 500 pounds per square inch 65 a period of time wherein reaction takes place consumingsaid paraflins and unsaturated-hydrocarbons, said added unsaturated hydrocarbons Vper cent by weight, subjecting ina second reaction zone a hydrocarbon material to a pyrolysis ltemperature above 1200 F. at a pressure less than 500 poundspersquare inch for a period of time such that an optimum yield of normally gaseous unsaturated l.hydrocarbons of the class.

leasta portion of said iirst added unsaturated version step containing predominantly parailln'f hydrocarbons, into said first reaction zone at a plurality of points during the period of time wherein reaction takes placeI separating from the emuents of said rst reaction zone a rst fraction Aconsisting of the heavier of the hydrocarbons of higher molecular weight so produced and removing it from the process, also separating a second l fraction containing at least a portion of the lighter 'of the hydrocarbons of higher molecular weight so produced and passing said' fraction to saidflrst reaction zone.

9. A process for converting hydrocarbons of low molecular weight into'a motor fuelof low and controlled volatility which comprises introducing to a process an initial hydrocarbon mixture comprised predominantly of parailln lhydrocarbons of not less than three and not morevthan ilve carbon atoms per molecule, adding thereto a recycle hydrocarbon mixture comprised of predominantly parain hydrocarbons of not less than three nor` m-ore than six carbon atoms per molecule, subjecting said" combined mixtures in a ilrst reaction zone to a pressure of between 500 and. 10,000 pounds per square inch and to a temperature of between 800 and 1200 F., concomitantly subjecting a normally gaseous hydrocarbon mixture in a second reaction zone toa pyrolysis temperature in excess of 1200 F. while under a pressure less than 500 pounds per square inch, for a period of time suillcient to produce normally gaseous unsaturated hydrocarbons of the class consisting of normally gaseous oleiins, acetylenes, and butadiene, adding to said mixture in said ilrst reaction zone said normally gaseous unsaturated hydrocarbons from said second reaction zone in a manner such that the. total concentration of unsaturated hydrocarbons does not exceed about per cent, separating from the eiiluents of said rst reaction zone a rst fraction comprised ofa gasoline boiling range hydrocarbon mixture of a low and controlled volatility and removing it from the process, separating a second fraction comprised of predominantly paraiiin hydrocarbons of not less than three nor morethan six carbon atoms per'molecule and containing controlled amounts of hydrocarbons of five and six carbon atoms per moleculeand returning said fraction to said rst reaction zone as said recycle hydrocarbon mixtureffjand further separating a third fraction of a lowen average molecular weight than said secondfraction and passing said third fraction to said second reaction zone,

10. A process for converting parain hydrocarbons of low molecular weight into higher molecular weight hydrocarbons, which comprises passing predominantly paralnic hydrocarbons which are predominantly ethane and propane through a iirst reaction zone and therein subjecting said hydrocarbons to a treatment under a pressure -less than 500 pounds per square inch and to a reaction temperature in excess of 1000" F. for a period of time sufilcient to produce a substantial amount o! ethylene, passing at least a portion of the efliuentsof said first reaction zone containing said ethyleneto a separating zone,..introducing to said process a parain hydrocarbon material of not less than three nor more than six carbon atoms per molecule, compressing at least a portion of said hydrocarbon material to a pressure between 1,000 and 10,000 pounds per square inch and subjecting said compressed material in a second-reaction zone to a temperature between 800 and 1200 F. causing reaction to 'take place consuming said hydrocarbon material and subsequently added ethylene, passing a iurther portion of said hydrocarbon material to said separating zone under a suitable pressure as an absorbent liquid and absorbing therein ethylene, introducing at least a portion of the resultant mixture under. a pressurev between 1,000 and 10,000 pounds per square inch and in an amount between about two and about ten per cent by weight of ethylene in the reaction mixture to said second reaction zone a plurality of times during Ithe course of the passage of the hydrocarbons passing therethrough, and iinally passing a hydrocarbonl stream from said second reaction zone to a separating zone and separating therefrom a fraction containing gasoline boiling range hyl drocarbons.

11. In a process for the production of higher boiling lhydrocarbons from lower boiling hydrocarbons, the step which consists in adding to a stream of predominantly saturated hydrocarbons, maintained at a conversion temperature and pressure, successive small quantities of predominantly acetylenic hydrocarbons, in such amount that the content of added acetylenes in the at no time exceeds 10 per cent by weight of the total hydrocarbons present.

'the said points being so,'spaced as to allow appreciable reaction to take place before the subsequent addition of further acetylene, and ma taining the content of added acetylene in the! ixture at not more than 10 per cent by weight of the hydrocarbons present therein.

13. A process for producing hydrocarbon mixtures containing at least 50 per cent of saturated hydrocarbons, which comprises heating a stream of predominantly saturated hydrocarbons to a decomposition temperature under a pressure in excess of approximately 4,000 pounds per square inch, adding acetylene-containing hydrocarbons to the said stream at a plurality of points, while maintaining the concentrationof added acetylenes in the resulting mixture at about 2 per cent by weight and separating the products from the unreacted hydrocarbons.

14. A process for the production of higher boiling hydrocarbons from'lower boiling hydrocardominantly saturated hydrocarbons, maintainedv bons of at least 2 carbon atoms per molecule which comprises adding to a stream of preat a conversion temperature and pressure,

, acetylenic hydrocarbons in such a manner and in such amounts that the concentration of acetylenic hydrocarbons in the resultant mixture undergoing reaction at no time exceeds l0 per cent by weight. Y

15. The process claimedl in claim 14 in which the concentration of acetylenic hydrocarbons is about 2 per cent.

16. A process for the production of higher boiling hydrocarbons from lowerboiling hydrocarbons of at least 2 carbon atoms per molecule which comprises adding to a stream or predominantly saturated hydrocarbons, maintained at a reaction temperature between 800 and 1200 1i. and a pressure of between 500A and 10,000 pounds per square inch, acetylenic hydrocarbons'in such a manner and in such amounts that the concentration of acetylenic hydrocarbons in the resultant mixture undergoing reaction at no time exceeds 10 per cent by weight.

17. A process for converting paraffin hydrocarbons of low molecular weight into higher molecular weight hydrocarbons which comprises passing predominantly paramnic hydrocarbons through a iirst reaction zone and therein subjecting said hydrocarbons to a pressure less than 500 pounds per square inch and a reaction temperature in excess of 1000 F. for period of time suiiicient to produce normally gaseous unsaturated hydrocarbons of the class consisting of normally 'gaseous oleilns,y

carbons so produced to a separating zone, introducing a paraffin hydrocarbon material of not less than 2 nor more than 6 carbon atoms per ,mixture molecule to said separating zone in liquid phase and under .a suitable pressure to absorb therein normally gaseous unsaturated hydrocarbons from f said portion of the eiiiuents from said ilrst rev action zone and introducing the resultant mixture into a body of predominantly parailin hyd'.o

undergoing conversion does not exceed 10 per cent by weight. Y

18. A process for producing gasoline boiling 'range hydrocarbons from predominantly parafnnic hydrocarbons, which comprises-passing normally gaseous predominantly paraillnic hydrocar- 1 bons through a ilrst reaction mue and therein of 5 and`6 carbon atoms per molecule and returning sald fraction tosaid first reaction zone as said recycled hydrocarbon mixture. and further-separating a third fraction of a lower average molecular weight than said second fraction and passing saidthird fraction to said second subjecting said hydrocarbons to a pressure less than 500 pounds per square inch into a reaction temperature for a period of time suillcient to produce normally -gaseous oleilin hydrocarbons, passing a portion of the eiiluents oi said -ilrst reaction zone containing said'normally gaseous oleiin hydrocarbons to a separating zone, compressing a mixture of predominantly parai'iinic hydrocarbons of not less than 3 nor more than 6 carbon atoms per molecule to a pressure in excess of 500 pounds per -square inch and subjecting a portion of said mixture in a second'reaction zone to a temperature of 800 to 1200 F. causing reaction to take 'place consuming paramns and subsequently added olefin hydrocarbons, passing a further portion of said mixture to said separating zone as an absorbent liquid and absorbing therein normally oleiln hydrocarbons produced in said first reactionzone, and introducing the resultant mixture in bons in the resultant mixture to saidsecond reaction zone a plurality of times during the course e .than 6 carbon atoms per molecule, subjecting a Ailrst portion of said' added mixtures in a first reaction zone to a pressure of between 500 and 10,000 pounds per square'inch and to a temperature of between 800 and 1200" F., concomitantly` subjecting a normally gaseous hydrocarbon mixture in a second reaction zone to a pyrolysis temperature in excess of 1200 F. while under a pressure less than 500 pounds per square inch for a period of time sumcient to produce normally gaseous olen hydrocarbons. passing a portion of the eliiuents of said 'second reaction' zone containing said normally gaseous olefin hydrocarbons to a separating zone, passing a second portion of said added mixtures as an absorbent liquid to said separating zone whereby normally gaseous olen hydrocarbons are absorbed in said liquid, adding to said portion of added mixture in said first reaction zone said normally gaseous olefin hydrocarbons and said absorbent liquid in a manner such that the total concentration oi' olen hydrocarbons does not exceed about 10% in said first reaction zone, separating from the eiiiuentsfof said first reaction zone a rst fraction comprised of 'a gasoline boiling range hydrocarbon mixture of a low and controlled volatility-and'removing it from the process, sepa- -rating a secondfiracti'on comprisedof predominantlyparamn hydrocarbons of not less than 3 nor more than 6 carbon atoms per molecule and containing controlled amounts othydrocarbons reaction zone. f

v20. A process for producing gasoline boiling range hydrocarbons from predominantly parat'-` nic hydrocarbons, which comprises passing predominantly paramnic hydrocarbons through a ilrst reaction zone and therein subjecting said hydrocarbons to a treatment under a pressure less than 500 pounds per square inch and to a reaction temperature in excess of 1,000 F., for a period of timesuillcient to produce normally gaseous oleiln hydrocarbons, passing at least a portion of the eiiiuents of said ilrst reaction zone containing said normally gaseous oleiln hydrocarbons to a separating zone, introducing to said process. a mixture of predominantly paraillnic hydrocarbons of not less than 3 normore than 6 carbon atoms per molecule, compressing at least a portion of said mixture to a pressure of between 500 and 10,000 pounds per square inch and subjecting said compressed mixture in a second reaction zone to a temperature between 800 and 1200 F., causing reaction to take place consuming paraiilns and subsequently added olefin hy- Vdrocarbons, passing a further portion of said mixturetosaid separatingzone under va suitable pressure as Aan absorbent liquid and absorbing therein normally gaseous olefin 'hydrocarbons produced vin said rst reaction zone, and introducing the resultant mixture under a pressure between 500 and 10,000 pounds per square inch and in amounts not to exceed 2 to 10% of olefin hydrocarbons in the reaction mixture to said second reaction zone a plurality oi' times during the course of the passage of the hydrocarbons .passing therethrough, and ilnally passing a hydrocarbon stream from said second reactionzone to a separating zone and separating therefrom gasoline boiling rangehydrocarbons.

l21. A process for converting paramn hydrocarbons of 2 or more carbon atoms per molecule to gasoline boiling range hydrocarbons o! controlled volatility, which comprises subjecting predominantly paramn hydrocarbons admixedwith normally gaseousA oleiln hydrocarbons in such a manner that the total concentration of oleilns in the mixture. at any one time does not exceed about 10% to a temperature between 800 and 1200 F., and a pressure greater than 500 pounds per square inch to, etiect conversion to predominantly saturated hydrocarbons of highermolecular weight, separating a -i'raction from the eiliuent of said conversion step containing pre- 'l f dominantly parailin hydrocarbonsof notv less than 2 carbon atoms per molecule and containing controlled amounts of predominantly paramn hydrocarbons oi from 5 to 6 carbon atoms per molecule, and admixing said traction with the fresh charge entering the conversion step.

22. A process for reacting parailin hydrocarbons with olen hydrocarbons to produce predominantly paraillnic products of higher mobons in such quantity tions of olens in the reaction mixture at no lecular weight including gasoline boiling range hydrocarbons of controlled volatility, which comprises charging a predominantly parafiinic hy` drpcarbon mixture of between 2 and 6 carbon atomsfpermolecule to a reaction zone, admixing therewith. oleilnic normally gaseous hydrocarthat the total concentratime exceeds about 10%, maintair'iing a reaction pressure exceeding 500 pounds per square inch and a reaction temperature between 800 and 1200 F. in said zone -to produce 'predominantly paranic reaction products, fractionating said products to recover a light fraction and a heavier fraction,the light fraction containing hydrocarbons of 5 and 6 carbon atoms per molecule in controlled amounts, recycling said light fraction to the reaction zone to increase the quantity of paraiiinic vproducts ,of 7 and more carbon atoms per molecule in the products of the reaction' step.

23. A process Afor converting hydrocarbons of low molecular weight into hydrocarbons of higher molecular weight; which comprises subjecting in a rst reaction zone a predominantly parailinic hydrocarbon fluid composed of hydrocarbons of not more than 6 carbon atoms per molecule and added normally gaseous oien hydrocarbons to a pressure above 500 pounds per square inch and a temperature between 800 and 1200 F. for a period of time wherein reaction takes place consuming said paraflins and olefin hydrocarbons, said added olefin hydrocarbons being added in a total amount between 2 and 30% by weight,

subjecting ina second reaction zone a hydrocarbon material to a pyrolysis temperature above 1200 F. at a pressure less than 500 pounds persquare inch for a period of time such that normally gaseous olefin hydrocarbons are produced, introducing said olen hydrocarbons so produced, as being at least a portion of said rst added olefin hydrocarbons, into said -rst reaction zone at a plurality o1.' points during the period of time wherein the reaction takes place, separating 4from the eiiiuents of said iirst reaction zone a rst fraction consisting of the heavier of the hydrocarbons of highermolecular weight so produced and removing it from the process. also separating a second fraction containing at least a portion of the lighter of the hydrocarbons of higher molecular weight so produced and passing said fraction to said first reaction zone.

24. A process for converting hydrocarbons of low'molecular weight into a motor fuel of low and controlled volatility, which comprises introducing to a process an initial hydrocarbon mixture comprised predominantly of parain hydrocarbons of not less than 3 and not more than 5 carbon atoms per molecule, adding thereto a recycle hydrocarbon mixture comprised of predominantly parain hydrocarbons of not less than 3 nor more than 6 carbon atoms per molecule, subjecting said combined mixtures in a rst reaction zone to a pressure of between 500 and 10,000 pounds per square inch and to a temperature of between 800 and 1200 F., concomitantly subjecting a normally gaseous hydrocarbon mixture in a.- second reaction zone to a pyrolysis temperature in excess of 1200 F. while under a pressure less than 500 pounds per square, inch for a period of time sudicient to produce normally gaseous olefin hydrocarbons. adding to said mixture in said iirst reaction zone said normally gaseous ciel-ln hydrocarbons from said second reaction zone in a manner such that the total concentration of olefin hydrocarbons is between about 2 and 10%, separating from the effluents vof said first reaction zone a.` rst fraction comprised of a gasoline boiling range hydrocarbon mixture of va low and controlled volatility. and

removing it from the process, separating a second fraction comprised of predominantly paramn hydrocarbons of not less than 3 nor more than 6 carbon atoms per molecule and containing controlled amounts of hydrocarbons of 5 and 6 carbon atoms per molecule and returning said fractionto said first reaction zone as,said recycle hydrocarbon mixture, and further separating the Athird fraction of a lower average molecular weight than said second fraction and passing said third fraction to said second reaction zone.

FREDERICK E. FREY.

- Patent No. 2,270,700.

CERTIFICATE 0F CORRECTION.V

' Jamiary 2Q, 19142. FREDERICK FREY' n y It is hereby certified that-errorappears in the printed .specifigzation ofthe above numbered ptent requiring correetions follows: Page 8 first oolmn, `1ine`28l-,. claim'l, after the word "nomallywinsert, --ggseous-v--g arid that thesaid Letters Patel-nt shbulclbe` read with this ccrrection there4-v in that .the same may confrmto the record of the case i the Patent Offie.

sima and sealed this 2in-,h day'of-narcn, .A. D. 191,12.

l. I Henry Arsiale, (S6111) Acting Gomis'sioner'ofiatents., 

